In a known manner, an electrochemical power source (a so-called “electrochemical cell”) comprises an electrochemical block (or stack), constituted by at least two electrodes, made of metal materials for example, with different electronegative potential, wherein a suitable electrolytic fluid is circulated.
This electrolytic fluid undergoes an increase in temperature when it is inside the electrochemical block, due to the exothermicity of the chemical reactions occurring inside the electrochemical block.
To avoid runaway thermal drift of the system, the electrolytic fluid is then usually extracted from the electrochemical block and cooled via suitable cooling systems, after which it is put back into the electrochemical block again.
Temperature control of the electrolytic fluid that is admitted into the electrochemical cell represents an important parameter for the correct operation of the power source, since, for example, it is correlated to the generated electrical power.
The use of a regulation system, which comprises a heat exchanger, two tanks designed to contain electrolytic fluid and a thermostatic valve, has therefore been proposed to implement temperature regulation of the electrolytic fluid.
In particular, electrolytic fluid at a higher temperature, defined as “hot”, such as that taken from the electrochemical block is poured into a first tank; a second tank, instead, contains electrolytic fluid at a lower temperature (defined as “cold”), obtained by opportunely cooling hot electrolytic fluid, which is made to flow through the heat exchanger.
The thermostatic valve has a first and a second inlet, respectively connected to the first and to the second tank, an outlet connected to a fluid inlet of the electrochemical block, and regulating means operable to control mixing of the hot electrolytic fluid and cold electrolytic fluid to be supplied to the electrochemical block, so as to adjust the temperature of the mixed electrolytic fluid.
However, the Applicant has found that design of this thermostatic valve poses some problems, in particular related to the variability of the operating conditions to which it might be subjected, for example, for different depths of use of the underwater vehicle, which could entail a corresponding variability in the circuit parameters at the inlet of the electrochemical block and therefore compromise the expected performance.